Hi
I have a list of start and stop dates for medications
I am trying to find if there is way to classify them to specifically
say if they are used in particular years
Med Start date Stopdate
xxx 11/12/2009 11/12/2012
yyy . 1/2/2010
zzz 1/1/2009 .
I want to create four variables Used_2009 used_2010 used_2011
used_2012
The criteria is
1)If medication is used even for a day in a year, it is considered to
be used for that year
2)If the start date is blank, then it is deemed to be used from a much
prior day
3)If ending date is blank/missing then that medication is currently active